music probs!!!!!!!

hi everyone im new to this so any help will be most welcome, had great fun so far with my 3gs iphone UNTIL i had to restore my laptop back to factory setting!!! i re installed itunes now when i conect my iphone it says that my phone is linked to another library!!!!! i can sync it but will lose all my music on my phone which i dont want to do but i cant put anymore on without losing what i have. plz help